The technology that enabled cool LEDs to replace hot high intensity discharge (HID) lamps for indoor grow lights for plants has enabled a revolution in another lighting category – outdoor solar lighting. This revolution has been made possible by the availability of bright white LEDs at reasonable prices. Solar lighting costs have declined to such an extent that solar is competitive in price with wired lights but offer far more convenience and significant operating cost savings.
Outdoor solar lights have improved greatly over the past couple of years and promise even more functionality in years to come. Why? Because solar is part of the green revolution and is drawing on the talents and energies of researchers, engineers and entrepreneurs.
How do they work? A solar panel, using photovoltaic cells, collects sunlight and converts it into electricity during the daytime. The electricity is stored in a rechargeable battery till it is needed at night to power an LED lamp (bulb). A photoresister prevents the lamp from being lit until after dusk. Because not a whole lot of electricity can be stored in a small battery, the amount of electric current that a light bulb consumes is an important consideration, since it determines how long the lamp will remain lit. In this area, newer brighter LEDs shine.
If you were to get only 30-60 minutes of light from a bulb after charging the battery all day, you probably wouldn’t bother. Which was the situation until higher wattage LEDs became fairly inexpensive. LED lamps are extremely efficient in their use of electricity. In some solar applications they can stay lit for 8 or 10 hours night after night for years, while costing nothing for power. So LEDs have made solar lighting the preferred type system in many outdoor lighting situations.
Advantages and disadvantages
Solar has many advantages over older-type wired lighting. First, there are no wires. So a solar fixturet can be conveniently put almost anywhere that you need it. That makes your walkways safer and enhances your outdoor living features. Second, solar lamps turn on at dusk and off at dawn, or whenever they run out of juice, so you can install them and forget them. Third, the electricity they consume comes from a totally free and limitless source – the sun – so solar lights have a very low maintenance cost.
Solar for outside lights also has two significant limitations. First, LED bulbs are not as bright as incandescent bulbs, so they will not work in applications that require very bright illumination over an extended period of time, such as some security applications. Second, the batteries will not get fully charged if sunlight is poor, so the lamps will not stay lit as long in winter or when the day was overcast or dark.
Outdoor lighting manufacturers typically aim for 8 hours of use on a fully charged battery. If it is half charged, which might be the case on an overcast winter day, a LED lamp might be lit for 4 hours, depending on the quality and age of the battery.
Uses of solar lights
Important uses of outdoor solar lights include
- Path lighting to light your walkway and driveway: Solar path lights direct light down, illuminating the ground around them. This has been the most frequent use for solar lighting.
- Garden lighting to accent landscape features. Applications and styles include uplights and spots to shine on shrubs and trees, floodlights for walls and building facades, path and string lights, water feature accent lights, and pool lights. Landscape design lighting is one of the fastest growing uses for solar.
- Party lights for your gazebo, deck or patio. Styles include tall stake lights in many designs, hanging lights, lights with party themes – often seasonal, umbrella lights, string lights, tiki torches, lighted snack bowls, table lamps, outdoor solar chandeliers, solar lanterns, and designs that will inspire your next outdoor party.
- Lighting for security applications, typically floodlights. While all require a large array of LEDs to provide sufficient brightness, they may be designed to remain on all night or incorporate motion detectors and stay on for short periods. Bright floods designed to stay on for the night will need a large PV panel and large battery capacity.
- Lighting innovation and advances in LED technology will bring more lighting design opportunities to the home and garden. And as white LEDs get brighter, more efficacious and less expensive, look for LED replacement lightbulbs eventually to replace incandescents and even CFLs. Look for increasing solar use in automotive, RV and boating applications.
Outdoor solar fixtures are available in many styles. Since LEDs are directional, they lend themselves to particular outdoor uses.
- Solar stakes are the easiest to use. Just push them into the ground. Down-facing or reflecting lamps are ideal for lining a walkway, path or driveway and for shining the way for visitors. Out-facing lamps provide ambient lighting for a patio. These may not be very bright, but will provide an enchanting ambience to walks and garden areas.
- Globe lamps can hang from shepherds hooks and patio umbrellas and even float in swimming pools. Tiki torches light a patio. Lamps attach to deck railings or string through bushes like Christmas lights. Solar chandeliers are popular in gazebos. The possibilities are virtually endless.
- Post-mount solar lights (post lights) replace wired lanterns atop posts, which are typically used at the sidewalk end or driveway end of a walk. Pole-mount solar lights (pole lights) are often used along a driveway. Column-mount solar lights (column lights) are set on existing brick or stone columns, used in pairs at the end of a drive. These are good applications for solar lights because they dispense with the wires, especially long runs, as well as the need to cross under the driveway.
- Wall-mount solar lights are typically used for security floodlighting in conjunction with an infra-red motion sensor. Security floods need to be bright. They will use up the battery’s stored electricity in a couple of hours. Nevertheless they can be useful if the light’s on-cycle is just a few minutes, such as for motion-activated lighting of a walkway for visitors.
- Solar lights with remote panels are used when the lamp itself is placed where it does not collect much sunlight. The lamp is wired to a solar panel a few feet away in a more open area that is exposed to more sunlight. These fixtures are often used where the lamp itself is hidden from view, such as a spotlight aimed at a façade or placed behind a bush.
- Decorative and fun styles of solar lights come in all sorts of shapes and have many uses. Typical are housings in the shapes of rocks or animals. Butterflies can flit through the garden, while rabbits and frogs provide whimsy in a children’s play yard.
Better quality fixtures are made of rust-resistant metals. There are stainless steel, copper, aluminum and wrought iron outside solar lights.
Fun styles are generally made of molded plastic or resin.
New ideas in solar lighting
As technology further improves and solar component costs continue to fall, engineers, architects and landscape architects are finding new uses for solar lighting in residential and commercial applications.
A high-priority target application is in retail stores in which incandescent spotlights are used to highlight displays. These hot lamps not only use a lot of electricity themseleves but they also add heat to the air that needs to be cooled. These two uses represent a large share of stores’ operating costs.
Hybrid solar/wired lighting uses large outdoor collectors that look like very bright satellite dishes to gather sunlight to run wired indoor lights in an office building during the daytime.
Hybrid solar/low-voltage wired lighting can light garden lamps or façade spotlights brighter and longer than solar systems alone.
The future of solar lighting includes nanotechnology that will sharply reduce the costs of illuminating interiors. Thin films are replacing crystalline PV panels on building roofs, and someday you may be able to paint your house with an inexpensive photovoltaic material.
Information on our site
On our site you will find articles describing many uses and styles of solar lighting, as well as solar products that may be perfect for enhancing the safety and beauty of your outdoor areas. Thank you for reading, and please let your friends know about Your Home — Your Castle.